Hydrocortisone in culture protects the blast cells in acute myeloblastic leukemia from the lethal effects of cytosine arabinoside

A phase II open-label study of aprepitant as anti-emetic prophylaxis in patients with acute myeloid leukemia (AML) undergoing induction chemotherapy

Despite the widespread use of 5-HT₃ antagonists as anti-emetic prophylaxis in patients with acute myeloid leukemia (AML) receiving induction chemotherapy, nausea and vomiting persist in many cases. We performed a Phase II single-arm study evaluating the use of aprepitant on days 1-5, in combination with a 5-HT antagonist on days 1-3, in AML patients undergoing induction chemotherapy with daunorubicin on days 1-3 plus cytarabine, given as a continuous infusion, on days 1-7. This was compared to a retrospective cohort of AML patients that received the same chemotherapy regimen with a 5-HT antagonist but without aprepitant. The cumulative incidence of vomiting/retching by the end of day 5 was significantly lower in the aprepitant vs. the control group (26.3 vs. 52.8%, p = 0.013). The cumulative incidence of nausea by the end of day 5 was 61% in the aprepitant group vs. 75% in the control group. The total use of supplemental anti-emetics on days 2-5 was also significantly lower in the aprepitant group (p = 0.01). In contrast, the cumulative incidence of vomiting/retching by the end of day 8, the incidence of vomiting/retching on days 6-8, and the use of anti-emetics on days 6-8, were not significantly different between the two groups. The results suggest that the use of aprepitant may be associated with a lower rate of emesis during aprepitant dosing days, but not afterward. However, this requires confirmation in a randomized trial.

Hematopoietic Protection by Dexamethasone or Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) in Patients Treated With Carboplatin and Ifosfamide

Based on preclinical studies, the authors undertook a pilot study to determine the hematologic and biologic effects of pretreatment with dexamethasone (Dex) or granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients receiving carboplatin and ifosfamide. Patients (n = 28) with metastatic solid tumors were randomized to receive pretreatment with Dex or GM-CSF or no pretreatment prior to courses 1 or 2 of carboplatin and ifosfamide. No alteration in dose of chemotherapy was allowed between course 1 and 2. Alterations of hematologic and nonhematologic toxicity and selected biologic parameters were compared between courses 1 and 2. Patients without any pretreatment demonstrated worsening hematologic toxicity in course 2 compared to course 1. In contrast, Dex pretreatment reduced hematopoietic toxicity and improved the absolute granulocyte count (AGC) and platelet count recovery times. For example, course 1 versus course 2 (with Dex pretreatment): AGC nadir (mm3) 153 versus 549 (p = 0.07), days AGC <500/mm3 7.8 versus 4.0 (p = 0.10), days to AGC recovery >1,500/mm3, 26 versus 22 (p = 0.034). Overall comparison between all five cohorts by analyses of variance demonstrated that intervention with Dex improved multiple hematopoietic toxicities, including AGC nadir (p = 0.015), and recovery times to AGC >1,500/mm3 (p = 0.07) and platelet count to >100,000/mm3 (p = 0.05). GM-CSF pretreatment did not worsen hematopoietic parameters after course 2 compared to course 1. Expected biologic effects of Dex and GM-CSF treatment were observed. Patients demonstrated an overall response rate of 32%, 1 complete response, and 8 partial responses. In patients with cancer, pretreatment with Dex or GM-CSF may significantly decrease the hematopoietic toxicity of chemotherapeutic agents.

In vitro effects of combination chemotherapy on osteoblasts: implications for osteopenia in childhood malignancy

Clinical studies suggest that combination chemotherapy adversely affects bone metabolism and in vitro studies have demonstrated that a reduction in osteoblast numbers results in diminished bone formation. The aim of this study was to investigate the in vitro effects of combinations of chemotherapeutic agents on primary human osteoblast-like (hOB) cell numbers and apoptosis, and to assess the ability of hOBs and osteoprogenitor (HCC1) cells to recover from prior treatment with chemotherapy. As glucocorticoids are frequently administered during treatment with cytotoxic agents, we evaluated whether glucocorticoids influence the chemosensitivity of hOB and human osteosarcoma (MG63) cells. Culture with clinically relevant concentrations of the individual chemotherapeutic agents reduced hOB cell numbers compared with control (p < 0.01) and also increased the numbers of apoptotic cells (p < 0.05). Potentiation of cytotoxicity was observed when agents were given in combination, thus further reducing cell numbers, and this effect was greatest when vincristine was given in combination with asparaginase. Following culture with a chemotherapeutic agent, there was greater recovery of hOB compared with HCC1 cell numbers (p < 0.01). Pretreatment with glucocorticoids ameliorated the adverse effects of chemotherapeutic agents on hOB and MG63 cell numbers and apoptosis (p < 0.05). We conclude that the use of combination chemotherapy contributes to osteopenia in childhood malignancy by a reduction in osteoblast numbers. However, this effect may be attenuated by the concomitant use of glucocorticoids.

Regulation of drug sensitivity by ribosomal protein S3a

When bcl-2 is immunoprecipitated from 32P-labeled cell extracts of all-trans retinoic acid (ATRA)-treated acute myeloblastic leukemia (AML) blasts, a phosphorylated protein of approximately 30 kd is coprecipitated. This protein has been identified as ribosomal protein S3a. The biologic effects of S3a include favoring apoptosis and enhancing the malignant phenotype. We sought to determine whether S3a, like bcl-2, influenced the response of cells to chemotherapeutic drugs and ATRA. Cell lines were studied in which S3a was genetically increased or disrupted; increased S3a was regularly associated with increased plating efficiency and increased sensitivity to either cytosine arabinoside (ara-C) or doxorubicin (DNR). S3a did not affect the sensitivity of cells to paclitaxel. Pulse exposures to either 3HTdR or ara-C showed a greater percentage of clonogenic cells in the S phase of the cell cycle in cells with increased S3a than in controls. Cells with increased S3a responded to ATRA by increased ara-C or DNR sensitivity, whereas cells with reduced S3a protein were either protected by ATRA or not affected. We studied cryopreserved blast cells from patients with AML or chronic myelomonocytic leukemia (CMML). S3a protein levels were heterogeneous in these populations. In 32 cryopreserved blast populations, S3a levels were significantly correlated with both bcl-2 and with cell growth in culture. As in cell lines, high S3a in cryopreserved blasts was associated with ATRA-induced sensitization to ara-C. No significant association was seen between S3a levels and response to treatment.

Stem cell renewal and determination during clonal expansion in normal and leukaemic haemopoiesis

Normal haemopoiesis is a cellular hierarchy headed by pluripotent stem cells capable of both self renewal and, after determination, the generation of differentiating lineages that end in terminal functional cells. The role of stem cells is crucial because only these have the capacity to generate clonal populations during development or after injury. During clonal expansion the cells are affected by many sets of receptors and ligands. These belong to at least two classes: one consists of growth factors that bind cell surface receptors and initiate signalling events; the other class contains receptors which act as ligand-dependent transcription factors such as the intracellular steroid superfamily. In spite of this elaborate regulatory apparatus, control during clonal expansion is lax, perhaps stochastic, as evident from the great heterogeneity disclosed by examining the cellular compositions of haemopoietic clones. It may be that the large number of signals impinging on binary possible outcomes (for example self-renewal or determination) serve to set probabilities rather than to determine outcomes. In leukaemia, many of the features of normal haemopoiesis are retained. The disease begins as transformations in normal stem cells; after additional leukaemogenic events clonal expansion yields malignant populations which are clonal in each affected individual. These dominant clonal populations retain the hierarchical organization found in the normal, the major difference is that post-deterministic divisions in leukaemia yield descendants that retain primitive (blast) morphology although proliferative capacity is lost. In acute myeloblastic leukaemia (AML) cell culture methods are available that permit the measurement of clonogenic blast stem cells. These methods have shown that regulatory mechanisms active in normal haemopoiesis are retained in AML, including lax regulation during clonal expansion. The biological features of blast stems cells displayed by the culture technique reflect in part, events in vivo, as associations have been found between results in cell culture and clinical outcome. Thus, study of leukaemic populations provides a challenge for basic science and an opportunity for successful application in control of disease.